Knitted anti-static and flame-retardant blanket

ABSTRACT

A knitted thermal blanket constituted of a material which is made of a combination of flame retardent synthetic yarns and flame retardent synthetic yarns containing a selected percentage of metal fibers that is selectively placed throughout the material either in the warp, the filling, or in both. The flame retardent synthetic yarn and metal combination is attained by spinning the synthetic fiber and metal fibers into a yarn and this yarn in the proper percentage needed is introduced into the fabric. The fabric is knitted in a manner whereby additional ties and knots hold the metal tighter and this prevents loss of the same during repeated washings of the material.

United States Patent [191 Gross 1 KNITTED ANTI-STATIC ANDFLAME-RETARDANT BLANKET [75] Inventor: Irving Gross, Providence, R].

[73] Assignee: Fairhope Fabrics, Inc., Fall River,

Mass.

221 Filed: Mar. 13, 1972 21 Appl. No.: 234,067

OTHER PUBLICATIONS Vol. 39, No. 28, July, 1970, Charles Reichman,

[ Apr. 30, 1974 Nomex: Promising Raw Material for Industrial Knits, pp.28, 29, 58 & 59,

Primary ExaminerCasmir A. Nunberg Attorney, Agent, or Firm-Alfred E.Miller [5 7] ABSTRACT A knitted thermal blanket constituted of amaterial which is made of a combination of flame retardent syntheticyarns and flame retardent synthetic yarns containing a selectedpercentage of metal fibers that is selectively placed throughout thematerial either in the warp, the filling, or in both. The flameretardent synthetic yarn and metal combination is attained by spinningthe synthetic fiber and metal fibers into a yarn and this yarn in theproper percentage needed is introduced into the fabric. The fabric isknitted in a manner whereby additional ties and knots hold the metaltighter and this prevents loss of the same during repeated washings ofthe material.

8 Claims, 2 Drawing Figures PATENTEDAPR30I974 3.806.959

WARP END n- WARP END WARP END 4 WARPEND KNITTED ANTI-STATIC ANDFLAME-RETARDANT BLANKET The present invention relates to a knittedthermal blanket of a highly flame retardent synthetic yarn in which ayarn containing fine metal fibers are blended into the fabric in amanner in which the metal fibers are retained therein, even afterrepeated washings, thus the present fabric shows a high degree of staticcontrol.

It is an object of the present invention to provide a knitted thermalblanket which has a combination of non-flammability and low staticpropensity.

Another object of the present invention is to provide a flame retardent,and anti-static mesh blanket which is knitted in a manner to ensure thatthere is no distortion of the mesh which would affect the wearability ofthe blanket.

The invention will now be more fully described with reference to theaccompanying drawings wherein:

FIG. 1 is a top plan view of the blanket fabricated in accordance withthe teachings of the present invention, and

FIG. 1A is a diagrammatic view showing the wrap ends and disclosing thepath of travel of the filling between the warp ends.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The blanket constructedaccording to the teachings of the present invention is similar in somerespects to my co-pending US. Pat. application Ser. No. 234,044 filedMar. 13, 1972 entitled Flame Retardent Blanket Having Anti-StaticProperties. In this regard, the synthetic yarn may take the form offlame retardent Verel staple, flame retardent Dynel staple, or any otherflame retardent synthetic staple. Verel is a registered trademark ofTennessee Eastman Company and is a modified acrylic staple havingbetween 35 and 85 percent acrylonitrile while Dynel is a registeredtrademark of Union Carbide Chemicals Company and is a modacrylic fiber.It should be noted that because of the excellent insulating propertiesof man-made synthetic yarn, such as Verel and Dynel, the electro-staticcharges built up in the fabric and are not permitted to dissipate, as isthe case with natural fabrics. Therefore, the use of flame retardentsynthetic yarns causes aserious problem of excessive build up of staticelectricity. In order to overcome this latter problem, it has beendiscovered that the placing of a certain proportion of extremely finelong metal fibers such as stainless steel throughout the blanket fabriccauses the static charge to be dissipated.

As seen in the drawing, the Verel warp ends 10a, 100, 10a, and 10g ofthe knitted thermal blanket show the use of extremely fine metal fibers12, such as stainless steel. The metal fibers 12 each'of a thickness ofapproximately 6-12 microns are blanded with a flame retardent Verel andspun into yarn. The resultant yarn is then placed in selected warps,such as, for example, every third warp end, i.e., 10a, 10c, 10f, etc.Moreover, if it is desired, for example, to have a three ply yarn twoends of plain Verel are twisted with the blended Verel yarn of flameretardent Verel having the metal fibers therein. It should be understoodthat the principal of the present invention may be achieved by placingthe metal fibers in each warp end, every other warp end, every thirdwarp end, etc. Moreover, it is to be understood that the presentinvention contemplates the placing of the metal fibers 12 in the fillingmaterial 14 or weft, and not in any warp ends at all. Furthermore, itshould be noted that the present knitted thermal blanket can be made inwhich part of the metal fibers 12 is in the warp yarn ends and the otherpart of the fibers 12 is located in the filling. It is also within thescope of the present invention to use yarn blended with metal in thefabric alone and without plying it with a selected synthetic yarn. Butin any event, the metallic fibers present in the knitted thermal blanketmust be so distributed in the knitted thermal blanket fabric in order torender the knitted thermal blanket conductive throughout. It may also bedesirable to place an excess amount of metal in the fabric in order tocompensate for small amounts of the metal fibers that may be separatedfrom the fabric after continued washings.

The amount of metal fibers in the knitted thermal blanket, that is, thesteel itself, has been calculated by weight with respect to the knittedthermal blanket, and the amount is preferably 0.23 percent. However,under certain circumstances, due to use in varying atmospheres, theamount of the metal fibers by weight may be more or less than the aboveamount but would be within the range of 0.10 to 2 percent by weight.

As seen in the drawing, the warp ends 10a, 100, etc., are for example,constituted of a synthetic staple, such as 8/2 ply Verel yarn and metalfibers 12 of a predetermined weight are twisted with the selected Verelyarn ends which may be every warp end, every second warp end, everythird warp end, etc.

As seen in FIG. 1A, the filling travels over three needles thereforeforming two filling ends A and B between each pair of needles or warpends. It should be noted that there are two filling devices operating in0pposite directions, thus resulting in four filling ends between eachpair of warp ends.

It should be observed that the present thermal blanket is of a knittedconstruction, such as a chain stitch. This knitted construction isdesirable because with soft synthetic yarn, such as Verel, there is acertain amount of slippage at the corners of the mesh resulting in adistortion of the mesh and reduces the wearability of a woven blanket.However, in the present knitted construction, each corner of the mesh isindividually locked by the knitting process and distortion is minimal.

The present knitted thermal blanket preferably has the yarn containingthe metal fibers knit in the warp with a knitted stitch as shown in thedrawing. Thus, additional ties and knots as a result of the knitting ofthe yarn hold the metal in the fabric much tighter thereby materiallyreducing the loss of this metal during continued washing of the knittedthermal blanket. Furthermore, the knitted thermal blanket is soconstructed that when the yarn containing the metal fibers 12 isin'every third, or in every second, or in every warp end, each row ofthe layed in filling 14 touches a metal-contained warp end.

It should be noted that the metal fibers 12 are so fine that they blendeasily with man-made fibers on conventional textile apparatus, and theycannot be seen or felt. The achievement resulting from the presentinvention is extremely desirable in our technological age, since boththe risk of fire and explosion remains a clear and present danger inhospitals and nursing homes, as well as the problem of disruption ofsensitive electronic equipment by static build up.

The present invention additionally contemplates the use of aflame-retardent synthetic fiber, such as Verel and Dynel, blended withother yarns, such as cotton. However, it is to be understood that theamount of flame-retardent synthetic fiber in the blend should besufficient to render the blanket substantially fire proof.

What is claimed is:

1. A knitted anti-static thermal blanket comprising a combination offlame retardent synthetic yarn staple fiber, and a blended yarncontaining a synthetic fiber and a plurality of metal fibers sodistributed in said fabric to render the same conductive throughout andto dissipate any electric charge therein, said metal fibers having aweight relative to said knitted thermal blanket of approximately 0.10 to2 percent whereby said knitted thermal blanket has both flame retardentand antistatic properties, said blanket being so knitted that said metalfibers are firmly held therein and during repeated washings of saidblanket the loss of metal fibers therein is materially reduced.

2. A knitted thermal blanket as claimed in claim 1 tional ties and knotswhereby said additional ties and knots in said knitted thermal blankethold said metal fibers therein.

3. A knitted thermal blanket as claimed in claim 2 wherein two plainwarp ends of synthetic yarn staple fiber are twisted in at least oneyarn end to form a mu]- ti-ply yarn.

4. A knitted thermal blanket as claimed in claim 1 wherein said yarncontaining said metal fibers is inserted in the filling material. I 5. Aknitted thermal blanket as claimed in claim 1 wherein a portion of saidyarn containing said metal fibers is twisted with at least one end ofsaid synthetic yarn to form the warp and the other portion of said yarncontaining said metal fibers is inserted in the filling material.

6. A knitted thermal blanket as claimed in claim 1 wherein each row ofthe layed in filling touches said blended yarn containing said metalfibers.

7. A knitted thermal blanket as claimed in claim 1 wherein saidsynthetic fiber is blended with another yarn.

8. A knitted thermal blanket as claimed in claim 7 wherein the warp endsare knitted in a chain stitch wherein said other yarn is cotton.

which functions to lock the corners and having addi-

1. A knitted anti-static thermal blanket comprising a combination of flame retardent synthetic yarn staple fiber, and a blended yarn containing a synthetic fiber and a plurality of metal fibers so distributed in said fabric to render the same conductive throughout and to dissipate any electric charge therein, said metal fibers having a weight relative to said knitted thermal blanket of approximately 0.10 to 2 percent whereby said knitted thermal blanket has both flame retardent and anti-static properties, said blanket being so knitted that said metal fibers are firmly held therein and during repeated washings of said blanket the loss of metal fibers therein is materially reduced.
 2. A knitted thermal blanket as claimed in claim 1 wherein the warp ends are knitted in a chain stitch which functions to lock the corners and having additional ties and knots whereby said additional ties and knots in said knitted thermal blanket hold said metal fibers therein.
 3. A knitted thermal blanket as claimed in claim 2 wherein two plain warp ends of synthetic yarn staple fiber are twisted in at least one yarn end to form a multi-ply yarn.
 4. A knitted thermal blanket as claimed in claim 1 wherein said yarn containing said metal fibers is inserted in the filling material.
 5. A knitted thermal blanket as claimed in claim 1 wherein a portion of said yarn containing said metal fibers is twisted with at least one end of said synthetic yarn to form the warp and the other portion of said yarn containing said metal fibers is inserted in the filling material.
 6. A knitted thermal blanket as claimed in claim 1 wherein each row of the layed in filling touches said blended yarn containing said metal fibers.
 7. A knitted thermal blanket as claimed in claim 1 wherein said synthetic fiber is blended with another yarn.
 8. A knitted thermal blanket as claimed in claim 7 wherein said other yarn is cotton. 